Valve for fuel burner

ABSTRACT

The invention relates to a system made of an oil pump and of a magnet valve for preventing oil from dripping when the oil burner is switched off. The inventive system is provided with an oil pump ( 23 ) and a magnet valve ( 10 ) which has a closing body ( 16 ) that comprises an oil flow borehole ( 17 ). The closing body ( 16 ) is displaceably located in a borehole ( 12 ). An oil line ( 11 ) goes through the borehole ( 12 ). The oil flow borehole ( 17 ) of the closing body ( 16 ) complements the oil line ( 11 ) in a first position of the inventive magnet valve ( 10 ). The oil flow is thus released. The closing body ( 16 ) interrupts the oil line ( 11 ) in a second position of the magnet valve ( 10 ). A vacuum is simultaneously generated in said second position. The vacuum reverses the direction of oil flow in an end section ( 15 ) of the oil line ( 11 ). The oil is thus prevented from dripping.

The invention relates to a system including an oil pump and of a valve,in particular a solenoid valve, for oil burners.

In oil burners, the fuel, which is oil, is sucked in from an oil tankwith the aid of an oil pump and is fed under pressure to an oil nozzle,as a rule to a pressure atomizer nozzle. At the pressure atomizernozzle, the fuel, that is to say the oil, is atomized into finedroplets, is mixed with injected air and is burnt in a flame. The flameis ignited by means of a corresponding ignition mechanism. It burnsindependently and in a stable fashion, as long as combustion air and oilare supplied to a sufficient extent and under appropriate conditions,such as, for example, sufficient pressure and suitable flow conditions.

In pressure atomizer nozzles of this type, dripping of the fuel, whichis oil, may commence when the burner is switched off. This oil thencollects, unburnt, in a burner space. This is a disadvantage, since,when the burner is restarted, there is in the burner space excess oilwhich is manifested in the form of unburnt hydrocarbons in the exhaustgas and thus considerably impairs the emission values of the burner.Also, since these unburnt oil residues may contaminate the burner mixinghead and the burner space to an extent such that, for example,undesirable soot may be built up and considerable burner disturbancesmay thereby be caused. Dripping of oil when the burner is switched offmust therefore be avoided.

The prior art, such as, for example, U.S. Pat. No. 5,799,871, EP 0 806246 and EP 0 731 315, discloses various nozzle shut-off valves which areintended to prevent the oil from dripping into the burner space when theoil burner is switched off.

Proceeding from this, the problem on which the present invention isbased is to provide a novel system which by simple design means preventsthe oil from dripping.

This problem is solved by means of a system having the features of claim1.

Further advantageous refinements of the invention may be gathered fromthe subclaims and the description.

A preferred exemplary embodiment of the invention is explained in moredetail below with reference to the drawing in which:

FIG. 1 shows a highly diagrammatic illustration of a system according tothe invention including an oil pump and of a valve, to be precise asolenoid valve, in a position releasing an oil flow, and

FIG. 2 shows a system according to the invention including the oil pumpand of the solenoid valve in a position blocking the oil flow.

The system according to the invention, illustrated in the drawing, bysimple design means prevents oil from dripping into a burner space of anoil burner not illustrated in detail.

FIG. 1 shows the system according to the invention in the form of acutout from an oil pump 23, on which is mounted a valve, to be precise asolenoid valve 10, which is arranged in the region of the inside-pumpoil line 11 (also called oil pressure line) which is interrupted by abore 12. The bore 12 accordingly subdivides the oil line 11 basicallyinto two portions 13 and 14, to be precise into a first portion 13 whichruns upstream of the bore 12 in the oil flow direction and into a secondportion 14 which is arranged downstream of the bore 12 in the oil flowdirection. An end portion 15 of the second portion 14 serves forcoupling to the nozzle assembly, not illustrated, having a pressureatomizer nozzle.

A closing body 16 is arranged within the bore 12. The closing body 16 ismounted so as to be axially displaceable within the bore 12.

According to FIGS. 1 and 2, the closing body 16 has an oil passage bore17. When the closing body 16 is in the position illustrated in FIG. 1,with the valve open, the oil passage bore 17 completes the inside-pumpoil line 11 and thus releases the oil flow from the oil tank in thedirection of the pressure atomizer nozzle. For this purpose, a centeraxis 18 of the oil passage bore 17 coincides with a center axis 19 ofthe oil line 11 in the region of the bore 12. Furthermore, the diametersof the oil passage bore 17 and of the oil line 11 in the region of thebore 12 are adapted to one another, that is to say they correspond toone another.

When the oil burner is to be switched off and the oil flow from the oiltank, not illustrated, in the direction of the pressure atomizer nozzle,likewise not illustrated, is to be interrupted, the closing body 16 ofthe solenoid valve 10 is displaced axially, to be precise is moved intothe position illustrated in FIG. 2. When the closing body 16 is in thissecond position, the inside-pump oil line 11 is interrupted by theclosing body 16. Furthermore, with the closing body 16 in this position,a reception space 20 is provided below the latter, thus resulting,within the portion 14 of the oil line 11 and therefore also within theend portion 15, in a vacuum being generated, as a result of which thedirection of the oil flow within the end portion 15 is reversed. In thisposition, therefore, the oil is drawn away from the pressure atomizernozzle of the oil burner and is collected in the reception space 20. Forthis purpose, the bore 12 is connected via a corresponding orifice 21 tothe second portion 14 of the oil line 11 and to the end portion 15.

It may also be noted, finally, that, in the exemplary embodimentillustrated in the drawing, the center axis 18 of the oil passage bore17 runs approximately perpendicularly to a center axis 22 of the closingbody 16.

It follows directly from the above description of the system accordingto the invention that dripping of the oil when the oil burner isswitched off is avoided. The system including the oil pump 23 and thesolenoid valve 10 has, so to speak, integrated oil return suction. Itmay be noted, for the sake of completeness, that other valves may alsobe used instead of a solenoid valve.

LIST OF REFERENCE SYMBOLS

10 Solenoid valve

11 Oil line

12 Bore

13 Portion

14 Portion

15 End portion

16 Closing body

17 Oil passage bore

18 Center axis

19 Center axis

20 Reception space

21 Orifice

22 Center axis

23 Oil pump

What is claimed is:
 1. A valve (10) for controlling the flow of a liquidthrough a delivery line (11), the valve comprising: a body, the bodyhaving bore (12) for receiving a closing body (16), the closing body(16) having a passage bore (17) which selectively passes the liquid froman upstream portion of the delivery line (11) to a downstream portion ofthe delivery line (11), wherein when the valve (10) is in a firstposition, a center axis (18) of the passage bore (17) coincides with acenter axis (19) of the delivery line (11) at least in the region of thebore (12) such that the passage bore (17) of the closing body (16)completes the delivery line (11) and thus releases flow of the liquidfrom the upstream portion of the delivery line (11) to the downstreamportion of the delivery line (11), and wherein when the valve is in asecond position, the closing body (16) interrupts the flow of the liquidfrom the upstream portion of the delivery line (11) to the downstreamportion of the delivery line (11), generates a negative pressure in atleast part of the bore (12) which is in fluid communication with atleast part of the downstream portion of the delivery line, and thus atleast temporarily reverses the flow of the liquid in at least a portionof the downstream portion (15) of the delivery line (11).
 2. A valve(10) as claimed in claim 1, characterized in that the closing body (16)is axially displaceable in the bore (12), and in that a center axis (18)of the passage bore (17) runs approximately perpendicularly to a centeraxis (22) of the closing body (16).
 3. A valve (10) as claimed in one ormore of claims 1 to 2, characterized in that, when the solenoid valve(10) is in the second position, the closing body (16) is displaced insuch a way that a reception space (20) for liquid is obtained within thebore (12).
 4. A valve (10) as claimed in claim 3, characterized in thatthe reception space (20) is in fluid communication with the downstreamportion of the delivery line.
 5. A valve (10) as claimed in one or moreof claim 1, 2, or 4, characterized in that the diameters of the passagebore (17) and of the delivery line (11) correspond to one another atleast in the region of the bore (12).
 6. A valve as claimed in claim 1wherein the liquid is a fuel oil.
 7. A valve as claimed in claim 6wherein the valve is in-line with the delivery line, and the deliveryline and valve pass the fuel oil from an oil pump to a burner.
 8. Avalve as claimed in claim 1 wherein the valve (10) is a solenoidcontrolled valve.
 9. A valve (10) for controlling the flow of a liquidthrough a delivery line (11), the valve comprising: a body, the bodyhaving bore (12) defined by side walls and at least one end wall, thebore (12) receiving a closing body (16), the closing body (16) having apassage (17) which selectively passes the liquid from an upstreamportion of the delivery line (11) to a downstream portion of thedelivery line (11), wherein when the valve (10) is in a first position,the passage (17) of the closing body (16) completes the delivery line(11) and thus releases a flow of the liquid from the upstream portion ofthe delivery line (11) to the downstream portion of the delivery line(11), and wherein when the valve is in a second position, the closingbody (16) interrupts the flow of the liquid from the upstream portion ofthe delivery line (11) to the downstream portion of the delivery line(11), and generates a negative pressure in a reception space (20)created in the bore (12) between the closing body (16) and the body,wherein the reception space (10) is in fluid communication with at leastpart of the downstream portion of the delivery line via an orifice thatextends though at least part of the end wall of the bore (12), and thusat least temporarily reverses the flow of the liquid in at least aportion of the downstream portion (15) of the delivery line (11).
 10. Avalve (10) as claimed in claim 9, characterized in that the closing body(16) is axially displaceable in the bore (12), and the passage (17)extends linearly through the closing body (16) along a center axis (18)that runs approximately perpendicularly to a center axis (22) of theclosing body (16).
 11. A valve (10) as claimed in claim 10,characterized in that, when the valve (10) is in the first position, thecenter axis (18) of the passage (17) coincides with a center axis (19)of the delivery line (11) in the region of the bore (12).
 12. A valve(10) as claimed in claim 9, characterized in that, when the valve (10)is in the second position, the closing body (16) is displaced away fromthe end wall of the body to create the reception space (20) between theclosing body (16) and the body.
 13. A valve (10) as claimed in claim 9,characterized in that the cross-sectional area of the passage (17) andthe cross-sectional area of the delivery line (11) correspond to oneanother at least in the region of the bore (12).
 14. A valve as claimedin claim 9 wherein the liquid is a fuel oil.
 15. A valve as claimed inclaim 14 wherein the valve is in-line with the delivery line, and thedelivery line and valve pass the fuel oil from an oil pump to a burner.16. A valve as claimed in claim 9 wherein the valve (10) is a solenoidcontrolled valve.
 17. A valve (10) for controlling the flow of a liquidthrough a delivery line (11), the valve comprising: a body having bore(12), wherein the bore (12) receives a closing body (16), the closingbody (16) having a passage bore (17) that extending through the closingbody, wherein when the valve (10) is in a first position, the passage(17) of the closing body (16) completes the delivery line (11) and thusreleases a flow of the liquid from an upstream portion of the deliveryline (11) to a downstream portion of the delivery line (11), and whereinwhen the valve is in a second position, the closing body (16) interruptsthe flow of the liquid from the upstream portion of the delivery line(11) to the downstream portion of the delivery line (11), and generatesa negative pressure in a reception space (20) that is in fluidcommunication with at least part of the downstream portion of thedelivery line and thus at least temporarily reverses the flow of theliquid in at least a portion of the downstream portion (15) of thedelivery line (11).
 18. A system comprising: an oil pump; a burner; adelivery line for delivering fuel oil from the oil pump to the burner; avalve in line with the delivery line, the valve including: a body havingbore (12), wherein the bore (12) receives a closing body (16), theclosing body (16) having a passage bore (17) that extending through theclosing body, wherein when the valve (10) is in a first position, thepassage (17) of the closing body (16) completes the delivery line (11)and thus releases a flow of the liquid from an upstream portion of thedelivery line (11) to a downstream portion of the delivery line (11) andto the burner, and wherein when the valve is in a second position, theclosing body (16) interrupts the flow of the liquid from the upstreamportion of the delivery line (11) to the downstream portion of thedelivery line (11), and generates a negative pressure in a receptionspace (20) that is in fluid communication with at least part of thedownstream portion of the delivery line and thus at least temporarilyreverses the flow of the liquid in at least a portion of the downstreamportion (15) of the delivery line (11) and away from the burner.
 19. Asystem as claimed in claim 18 wherein the valve (10) is a solenoidcontrolled valve.